<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
         article{
            width:500px;
            height:200px;
            background-color: #ccc;
            margin:0 auto;/*水平居中*/
        }
        article>div.left{
            width:200px;
            height:200px;
            background-color:aqua;
            float:left;
        }
        article>div.right{
            width:200px;
            height:200px;
            background-color:brown;
            float:right;
        }
        article>div.content{
            height:200px;
            background-color:pink;
            margin-left:200px;
            margin-right:200px;
        }
    </style>
</head>
<body>
    <article>
        <div class="left"></div>
        <div class="right"></div>
        <div class="content"></div>
    </article>
</body>
</html>